<template>
  <div id="app">
    <router-view v-if="isRouterAlive"></router-view>
  </div>
</template>


<script>
import HelloWorld from "./components/HelloWorld";

export default {
  name: "app",
  components: {
    HelloWorld,
  },
  created() {
    // 在页面加载时读取sessionStorage里的状态信息
    if (sessionStorage.getItem("store")) {
      this.$store.replaceState(
        Object.assign(
          {},
          this.$store.state,
          JSON.parse(sessionStorage.getItem("store"))
        )
      );
    }

    // 在页面刷新时将vuex里的信息保存到sessionStorage里
    // beforeunload事件在页面刷新时先触发
    window.addEventListener("beforeunload", () => {
      sessionStorage.setItem("store", JSON.stringify(this.$store.state));
    });
  },

  provide() {
    return {
      reload: this.reload,
    };
  },
  data() {
    return {
      isRouterAlive: true,
    };
  },
  methods: {
    reload() {
      this.isRouterAlive = false;
      this.$nextTick(() => {
        this.isRouterAlive = true;
      });
    },
  },
};
</script>

<style>
#app {
  font-family: "Avenir", Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  /* text-align: center; */
  color: #2c3e50;
}
</style>
